Steinmeier, making the first state visit to Thailand by a German president since 2002, joined Srettha to inspect a guard of honour at Government House.
Thai Cabinet ministers and military and police chiefs were also on hand to greet the German head of state and his entourage.
Srettha and Steinmeier then led talks between government ministers from both countries.
The Thai PM has styled himself as a “salesman for the country” since taking office last August, touting investment and trade opportunities on the international stage. Among them is the 1-trillion-baht (US$28 billion) land bridge project to open a new global trade route linking the Pacific and Indian oceans via Chumphon and Ranong.
Also present at Thursday’s talks were Commerce Minister Phumtham Wechayachai, Foreign Minister Parnpree Bahiddha-Nukara, and Transport Minister Suriya Juangroongruangkit.
Germany’s delegation included Hubertus Heil, minister of labour and social affairs, and Michael Kellner, state secretary at the Ministry for Economic Affairs and Climate Action.
Business representatives also participated in the talks.
Both leaders witnessed the signing of bilateral pacts for cooperation on rail systems and science.
PM Srettha also hosted a lunch for the visiting German leader and his wife at Government House.
Government spokesman Chai Wacharonke said Thailand is aiming to upgrade relations with Germany to strategic partnership status.
The talks aim to enhance cooperation on trade, investment, energy, security, and climate change challenges, helping to improve Thailand’s image on the international stage, he added.